Infections - Soft Tissue - Hand Flashcards
A 67-year-old man with type 1 diabetes mellitus is evaluated for full-thickness perineal burns sustained by falling onto a space heater. Forty-eight hours after admission, he has onset of fever and tachycardia. Complete blood cell count shows leukocytosis, and wound culture was positive for gram-negative rods consistent with Pseudomonas. Pending sensitivity report, empiric coverage is initiated. Which of the following antibiotics is clinically CONTRAINDICATED for initial therapy?
A) Ceftazidime
B) Ceftriaxone
C) Ciprofloxacin
D) Imipenem
E) Tigecycline
The correct response is Option E.
Although tigecycline has excellent coverage of most staphylococcal and many gram-negative rod infections, this tetracycline derivative is not effective against pseudomonal infections. Patients with pseudomonal sepsis benefit from double coverage. Furthermore, sensitivities to different antimicrobial agents are quite variable from one health care system to another, so providers must remain vigilant after beginning therapy and change coverage based on lack of clinical response and determination of final sensitivities. An essential component of this patient’s care would be urgent burn wound excision, after he has been resuscitated and empiric antibiotics have been initiated.
Verruca vulgaris (common wart) and verruca plana (flat wart) are similar in which way?
A) Rate of occurrence
B) Likelihood of spontaneous resolution
C) Pathologic appearance
D) Risk of transforming to carcinoma
E) Human papilloma virus etiology
The correct answer is option E.
Warts are more common in childhood. The rate of occurrence of common to plane warts is 20 to 1. Both can spontaneously resolve but the plana type is more likely to do so. The pathologic findings are different. Both have koilocytes, large keratinocytes with eccentric nuclei and perinuclear halo. The verruca plana lack parakeratosis and papillomatosis which are present in the vulgaris. Transformation to carcinoma has been reported with verruca vulgaris.
Persons with immunosuppression are at increased risk for this change. Both forms are caused by epidermal infection with the HPV virus, the common wart from HPV types 1, 2, 4, and 7, and the plane wart from HPV types 3, 10, 27, and 41.
A 59-year-old man with type 2 diabetes mellitus comes to the office because he has had swelling, pain, and decreased function of the right small finger after he injured it slightly 2 weeks ago. The patient reports similar symptoms of the right thumb, although it sustained no inciting injury. Examination of both digits shows signs and symptoms of pyogenic flexor tenosynovitis. In addition to washing out the respective tendon sheaths, exploration of which of the following additional sites is necessary?
A) First web space
B) Flexor carpi radialis tendon sheath
C) Hypothenar compartment
D) Ring finger flexor tendon sheath
E) Space of Parona
The correct response is Option E.
Infectious flexor tenosynovitis can spread from the tendon sheath of the fifth digit to the flexor tendon sheath of the thumb by way of the space of Parona: the potential space in the volar wrist, deep to the flexor tendons but superficial to the pronator quadratus muscle. In this area, the proximal extent of the tendon sheaths of both the small finger and the thumb are in close proximity. This has been termed the “horseshoe abscess” of the upper extremity.
A 38-year-old man undergoes extensive debridement of skin, subcutaneous tissue, and fascia on the right chest wall (shown) for progressive Type II monomicrobial necrotizing fasciitis. Results of culture are pending. In combination with penicillin, which of the following antibiotics is the most appropriate initial therapy?
(A) Ciprofloxacin
(B) Clindamycin
(C) Gentamicin
(D) Metronidazole
(E) Vancomycin
The correct response is Option B.
Necrotizing fasciitis is a severe form of subcutaneous infection that tracks along fascial planes often extending beyond the superficial signs of infections. Early diagnosis and treatment are critical in reducing mortality. Early surgical intervention is often required for diagnosis and treatment.
Initial antibiotic therapy is directed at the most likely pathogens. Two clinical subtypes of necrotizing fasciitis have been identified. Type I is a polymicrobial infection caused by aerobic and anaerobic bacteria occurring primarily in patients who are immunocompromised or have certain chronic diseases like diabetes.
Type II is a monomicrobial infection that can occur in healthy individuals in any age group. Often, the individual has a history of blunt trauma, penetrating injuries or lacerations (often minor), surgical procedures, childbirth, or burns.
In Type II fasciitis, the most common causative organisms are group A streptococci. Clindamycin and penicillin in combination are recommended. Clindamycin has been shown to suppress toxin production, whereas metronidazole has not. Clindamycin also facilitates phagocytosis of Streptococcus pyogenes. Penicillin is added because of increasing resistance of group A streptococci to clindamycin.
Infection with Staphylococcus aureus is a less common cause of Type II necrotizing fasciitis. Oxacillin could be used to treat susceptible S. aureus infection, whereas vancomycin is appropriate therapy for methicillin-resistant S. aureus (MRSA).
Type I necrotizing fasciitis requires a multiple antibiotic regimen to cover aerobic and anaerobic bacteria. Therefore, broad €‘spectrum coverage with ampicillin €‘sulbactam, clindamycin, ciprofloxacin, or gentamicin is recommended.
A 55-year-old man who is a commercial fisherman comes to the office because of a 3-week history of a swollen index finger. The patient holds the finger in a flexed position. Extension of the digit is difficult but not painful. Surgical exploration shows nonpurulent fluid in the tendon sheath. Culture of the fluid is most likely to show which of the following pathogens?
A) Eikenella corrodens
B) Mycobacterium marinum
C) Sporothrix schenckii
D) Staphylococcus aureus
E) Vibrio vulnificus
The correct response is Option B.
The patient described has an occupation that exposes him to contaminated water and raw seafood. Infections from Mycobacterium marinum and Vibrio vulnificus are both possible.
Mycobacterium marinum is the most common atypical mycobacterium seen in hand infections, often seen after penetration by aquatic equipment, colonized marine life, or contact with contaminated water. The most common deep infection is flexor tenosynovitis, and may present as a chronic tenosynovitis.
Sporothrix schenckii is a fungus found in plants and soil. Inoculation with the pathogen results in a papule at the entry site, followed by development of lesions along the lymphatic chain.
Suppurative flexor tenosynovitis typically presents with pain over the tendon sheath, semiflexed position of the involved digit, pain on passive extension, and symmetrical swelling of the finger. This classic presentation is commonly caused by pathogens such as Staphylococcus aureus or Eikenella corrodens (often seen in association with human bite injuries). In tenosynovitis infections involving atypical mycobacterium, however, there is absence of pain.
Vibrio vulnificus is a species of gram-negative, motile, curved bacterium found in the coastal waters of the United States. Infections from V vulnificus may be caused by direct exposure of an open wound to warm seawater containing the organism or from handling raw seafood or marine wildlife. Infections caused by V vulnificus result in painful cellulitis that progresses rapidly and presents with marked local tissue swelling with hemorrhagic bullae. Bacteremia with systemic symptoms is commonly seen.
A 25-year-old man who is a soldier from Afghanistan is evaluated because of deep frostbite of the right hand after being in the field for 36 hours. Rewarming is performed in the field. He is transferred to a hospital for further evaluation. Physical examination shows hemorrhagic blisters and eschar formation on the hand, erythema of the surrounding area, and streaking up the forearm. Which of the following is the most appropriate next step in management?
A ) Administration of dextran
B ) Administration of penicillin
C ) Hyperbaric oxygen therapy
D ) Intra-arterial injection of reserpine
E ) Observation
The correct response is Option B.
Field management for frostbite includes rapid rewarming of the affected area with circulating water at 104 to 107.6 °F (40 to 42 °C) for a period of 15 to 30 minutes, protection from mechanical trauma, and appropriate analgesia.
Next steps in management include elevation, antitetanus prophylaxis, debridement of clear blisters, leaving hemorrhagic blisters intact, and application of aloe vera. Penicillin should be administered for cellulitis.
Adjuvant therapies can include anticoagulation, thrombolytics, hyperbaric oxygen, and sympathetic blockade; however, data to support these therapies are scant and equivocal at best. Definitive surgical amputation should be delayed for at least 3 weeks to allow for tissues to demarcate, in terms of viability.
A 22-year-old man who has type 1 diabetes mellitus comes to the office because of a 1-day history of cervical and chest pain. Temperature is 102.2°F (39.0°C). Physical examination shows right-sided cervical erythema and moderate swelling. A broad-spectrum antibiotic is administered, and he undergoes incision and drainage. During the procedure, extensive soft-tissue necrosis not confined by fascial planes is noted. Which of the following is the most likely cause of this infection?
A) Mastoiditis
B) Meningitis
C) Parotitis
D) Pharyngitis
E) Sinusitis
The correct response is Option D.
The patient described has cervical necrotizing fasciitis (CNF) that likely extends into the mediastinum. Pharyngeal and tonsillar infections, along with dental abscesses, are the most common sources of infection. Diabetes and other immunocompromised states are frequent comorbidities in this disease. Early presentation may be clinically indistinguishable from a superficial soft-tissue infection and, therefore, requires a high index of suspicion. Skin necrosis is often a late finding, as the infection begins in the fascial and deep tissues of the neck. CT scan is usually obtained to define the extent of the disease and may or may not show gas within the soft tissues. Patients are treated with broad-spectrum antibiotics and aggressive surgical debridement.
Mastoiditis is an infection of the mastoid air cells usually arising in the setting of untreated otitis media. Mastoiditis can spread to surrounding structures, including the brain.
Meningitis is an infection of the meninges that is associated with neck pain as well as fever, headache, and photophobia. It does not present with unilateral neck erythema and swelling.
Parotitis is an infection of the parotid gland that usually arises in the setting of an obstructed parotid duct and is a very rare but potential cause of CNF.
Sinusitis is not usually associated with CNF but may spread to the orbit, resulting in orbital cellulitis or orbital abscess, and, occasionally, cavernous sinus thrombosis. Cavernous sinus thrombosis is a life-threatening condition.
A 33-year-old snake handler has diffuse swelling of the left hand and forearm after being bitten by a pit viper. The venom was directly injected into the skin and subcutaneous tissue of the forearm. When establishing a diagnosis of compartment syndrome in this patient, which of the following is the earliest clinical finding?
(A) Accentuation of pain by passive muscle stretching
(B) Diminished sensation in the affected compartment
(C) Obliteration of distal pulses by compartment swelling
(D) Persistent, worsening pain
(E) Tenseness on palpation of the compartments of the forearm
The correct response is Option A.
This patient has compartment syndrome due to a snake bite. Pain is the hallmark of compartment syndrome and is accentuated by passive stretching of the involved muscle compartment, which is the most consistent early sign. Patients with injuries of the upper and lower extremities should be closely monitored for the presence of muscle, nerve, and tissue ischemia. However, compartment syndrome occurring in conjunction with a pit viper or other snake bite is often worse than other types of compartment syndrome. Because the venom is injected directly into the tissues, tissue destruction occurs rapidly, leading to the immediate onset of edema, ecchymosis, and swelling.
Measurement of compartment pressures is an important step in the diagnosis of compartment syndrome, especially in patients who have sustained head trauma or spinal cord injuries. Decompressive fasciotomy should be performed in normotensive patients when compartment pressures are greater than 30 mmHg and the duration of symptoms is longer than eight hours or is unknown or the patient is unconscious or uncooperative. Patients with hypotension and compartment pressures greater than 20 mmHg should also undergo surgery within six hours.
In some patients with compartment syndrome, central or peripheral sensory deficits or late nerve ischemia may preclude the presence of pain as a diagnostic finding.
In compartment syndrome, distal pulses may still be present. The affected extremity may appear cyanotic, pale, or normal. Sensation may be normal or diminished.
Tenseness and tenderness of the closed compartments are nonspecific findings that are not necessarily associated with ischemic tissue damage.
A 45-year-old man has a two-day history of pain and swelling of the proximal interphalangeal joint of the right index finger. Physical examination shows pain on passive motion of the affected joint and erythema and tenderness extending into the right hand. Gram €™s stain of fluid aspirated from the joint shows gram-positive cocci.
199.
A 19-year-old man has a seven-day history of swelling and pain on the volar surface of the left index finger. He has no history of trauma to the finger. Gram €™s stain of fluid aspirated from the joint shows gram-negative diplococci.
The correct response for Item 198 is Option B and for Item 199 is Option E.
Septic arthritis may result from extension of an adjacent subcutaneous abscess or by intra-articular contamination caused by a laceration or puncture wound. The joint is a poorly vascularized potential space, favoring colonization. Early diagnosis and drainage are crucial to treatment, as a joint infection can progress rapidly to destruction of articular cartilage.
The two most common organisms that cause hand infections are Staphylococcus aureus and B €‘hemolytic streptococci. Minor staphylococcal and streptococcal infections are treated with first-generation cephalosporins. More significant infections of the interphalangeal joint should be performed through a midaxial incision.
Neisseria gonorrhoeae usually manifests as a primary venereal infection. However, it can
disseminate and sometimes present as a secondary hand infection, which is often confused with a purulent tenosynovitis or arthritis. It is important to distinguish gonococcal from pyogenic infection because, unlike a pyogenic infection, a gonococcal infection does not usually destroy tendon or articular cartilage. Therefore, incision, drainage, and debridement are unnecessary and should be avoided. Disseminated gonococcal infection is the most common cause of acute infectious arthritis in sexually active adults. A history or evidence of trauma are lacking. Fluid aspiration with Gram staining for gram €‘negative diplococci allows definitive diagnosis. Hospitalization and intravenous administration of a third €‘generation cephalosporin is recommended.
Manifestations of Sweet syndrome can masquerade as acute hand infections. Sweet syndrome, originally described as an acute febrile neutrophilic dermatosis, belongs to a class of skin lesions that histologically have intense epidermal and/or dermal inflammatory infiltrate of neutrophils without evidence of infection or vasculitis. The lesions can erupt at sites of minor trauma. The clinical picture is consistent with infection initially. The unresponsiveness of these lesions to antimicrobial therapy and the lack of associated cellulitis is a clue to the diagnosis. The treatment of choice involves a tapering dose of corticosteroids.
Herpetic whitlows are often confused with paronychia or felon and are treated mistakenly as such. Initial signs include intense pain and erythema of the fingertip, followed by edema and tenderness. A Tzanck smear of vesicular fluid may show multinucleated giant cells. Primary herpes simplex infections typically resolve without treatment within three weeks. Incision and drainage of herpetic whitlow is contraindicated because surgical treatment converts a closed wound to open and may result in a secondary bacterial infection or viral superinfection. To date, there have been no controlled studies that assess the efficacy of acyclovir for the treatment of herpetic whitlow, b
An otherwise healthy 35-year-old man comes to the emergency department because of a 2-day history of swelling and pain in the index and long fingers of the right hand. He reports pain when he attempts to flex these fingers or bring them together. Physical examination shows no pain with passive extension of the fingers or during axial loading. There is pain with passive adduction of the fingers. A photograph is shown. Which of the following is the most appropriate management?
A) Arthrotomy of the metacarpophalangeal joint of the long finger
B) Division of ulnar-sided Cleland ligament of the index finger
C) Dorsal and volar incisions in the proximal second web space
D) Drainage of the mid-palmar space
E) Release of the A1 pulley of the index and long fingers
The correct response is Option C.
The patient described has a web space (collar-button) abscess. Pus resides dorsal to and volar to the natatory fibers of the palmar fascia with a small connection between the two spaces passing through the natatory fibers. It is drained through proximal dorsal and volar incisions in the web space. One should not incise through the apex of the web space, as this may lead to a web space contracture.
Incisions are allowed to heal by secondary intention.
Cleland ligament is a separate portion of the palmar fascia located within the finger dorsal to the neurovascular bundle. It is distal to the purulence in a web space abscess. Absence of pain with axial loading of the digits makes a joint space infection unlikely, so drainage of the metacarpophalangeal joint is unnecessary. Some approaches to drainage of flexor tenosynovitis involve release of the proximal sheath through the A1 pulley; the appearance in the photo (lack of fusiform swelling), and absence of pain with passive extension of the fingers, make flexor tenosynovitis unlikely in this patient. Infection of the mid-palmar space would produce more proximal pain and swelling in the palm, which is not present in this patient.
A 50-year-old man has had the fingernail deformity shown in the photograph above for the past year. There is no history of trauma to the finger. Which of the following is the most appropriate management?
(A) Topical administration of neomycin ointment twice daily
(B) Oral administration of ciprofloxacin 400 mg twice daily
(C) Oral administration of terbinafine 250 mg daily
(D) Resection of the involved sterile matrix and grafting from the matrix of the great toe
(E) Surgical removal of the nail plate and stenting of the eponychial fold with nonadherent gauze
The correct response is Option C.
This patient has a dystrophic nail resulting from a fungal infection (onychomycosis). The diagnosis of onychomycosis can be confirmed by positive findings on fungal culture. Fungal infections are the underlying cause of dystrophic nails
in approximately 50% of affected patients; the remaining 50% are caused by other factors, including psoriasis, lichen planus, and trauma. Although they are more common in the foot, fungal infections can cause functional and aesthetic deformities in the fingernails.
In the past, long-term administration of antifungal agents was recommended; however, this treatment course was associated with significant toxicity, requiring monitoring of hepatic function, and often disappointing results. More recently, terbinafine and itraconazole have offered new treatment options. This agents are administered for six weeks, and hepatic function is monitored only in those patients who have a history of hepatitis, liver disease, or heavy alcohol use. However, adverse effects associated with terbinafine use include Stevens-Johnson syndrome, neutropenia, hepatotoxicity, hepatic failure, erythema multiforme, toxic epidermal neurolysis, and anaphylaxis. In addition, terbinafine is far more costly than previously used antifungal agents.
Topical or oral administration of antibiotics would not be expected to improve this fungal infection. In addition, topical antibiotics may aggravate the nail matrix. Resection of the sterile matrix and replacement with a graft is associated with a high incidence of recurrence and morbidity. Removal of the nail would not eliminate the fungal infection within the underlying matrix.
A 21-year-old woman has swelling and edema of the left index finger two days after sustaining a puncture wound to the finger. Which of the following is the most sensitive indicator of bacterial flexor tenosynovitis in this patient?
(A) Diffuse erythema of the finger
(B) Drainage from the wound
(C) Fusiform swelling of the finger
(D) Pain on passive extension of the finger
(E) Tenderness along the flexor tendon sheath
The correct response is Option D.
Tenosynovitis is a bacterial infection within the sheath of the extrinsic flexor tendons of the hand. Suppurative infection of the sheath can develop over time. Classic signs of tenosynovitis include fusiform swelling, partial flexed posturing of the digit, and tenderness along the flexor tendon sheath; however, other inflammatory processes can cause these findings. In contrast, the fourth classic sign, pain with passive extension of the digit, is the most sensitive test for flexor tenosynovitis. Aspiration of the affected tendon sheath will yield purulent drainage. Diagnosis can be confirmed with Gram’s stain.
In patients with established tenosynovitis, the most appropriate management is surgical irrigation and/or drainage of the tendon sheath. This is best accomplished with a proximal incision at the level of the A1 pulley and a distal incision at the distal flexor crease; the fibroosseous canal is then irrigated copiously. In patients with more extensive infection, open drainage and debridement may be required.
Drainage from a finger wound is more likely to be caused by local wound infection than by tenosynovitis.
A 34-year-old man is brought to the emergency department after sustaining a snake bite to the dominant right thumb. A photograph is shown above. The patient has severe pain, nausea, and vomiting. On examination, the distal forearm is tense. Prothrombin time and partial thromboplastin time are increased. The snake has been captured and was brought to the emergency department by the patient; a photograph is shown above.
Which of the following is the most appropriate management?
(A) Elevation of the extremity, application of ice, and intravenous administration of antibiotics
(B) Elevation of the extremity, application of ice, intravenous administration of antibiotics, and administration of antivenin
(C) Incision and suction drainage of the bite wound, elevation of the extremity, application of ice, and intravenous administration of antibiotics
(D) Fasciotomy and intravenous administration of antibiotics
(E) Fasciotomy, intravenous administration of antibiotics, and administration of antivenin
The correct response is Option E.
This patient who has sustained a pit viper bite to the dominant right thumb requires immediate treatment involving fasciotomy, intravenous administration of antibiotics, and administration of pit viper antivenin. Approximately 98% of venomous snake bites are from pit vipers, and more than 70% of these bites involve the upper extremity. Pit vipers can be distinguished from other snakes by the presence of two retractable maxillae, each of which contains a fang for envenomation. In patients who sustain pit viper bites, immediate first aid should consist of patient reassurance, immobilization of the affected limb and placement of the limb on a level plane, and transportation to a hospital as soon as possible. Envenomation should be assumed with the presence of fang marks and rapid swelling of the extremity; broad-spectrum antibiotics should be administered immediately in the emergency department. Patients who have tense edema of the affected extremity and compartment pressures of greater than 30 mmHg should be diagnosed with compartment syndrome. Urgent fasciotomy should be performed.
Because snake venom can greatly worsen myonecrosis and systemic findings, antivenin should be administered to any patient who has systemic symptoms of envenomation associated with increased laboratory values. Following administration of a test dose, five to 10 vials of snake antivenin are typically administered in patients who do not exhibit allergic sensitivity. A central line should be placed and emergency resuscitation should be available. The administration of as many as 20 vials of antivenin may be required in patients who have extreme abnormalities on laboratory evaluation.
Application of ice will result in vasoconstriction, ischemia, and tissue necrosis. Incision and suction drainage of the bite wound should be performed within 15 minutes of the bite.
A 56 year-old sheep farmer is bitten on his finger by one of his sheep. Three weeks later he complains of a large painless nodule at the site of the injury. Examination reveals a 1.5 cm diameter raised nodule on the dorsum of his finger with a central open area covered with a thin crust. There is no surrounding erythema or induration. Recommended treatment for this patient is:
A) Observation
B) Broad spectrum parenteral antibiotics
C) Topical antifungal agents
D) Excisional biopsy and local flap coverage
E) Finger amputation
The correct answer is option a.
This patient has developed an infection caused by a member of the poxvirus family that is endemic in sheep and goats. In humans the infection is known as human orf infection. An identical infection may occur from contact with infected cattle in which case it is known as milkers’ nodule. In either case the disease is self limiting and typically resolves within six weeks in immunocompetent hosts. Failure to recognize the correct diagnosis may lead to unnecessary surgical interventions including amputation.
A construction worker has an abscess of the palm of the nondominant hand after sustaining a puncture wound to the palm. In this patient, the midpalmar space is defined by which of the following boundaries?
(A) Flexor tendons, abductor pollicis muscle, superficial aponeurosis, and septum from the second metacarpal bone to the flexor digitorum profundus sheath
(B) Flexor tendons, metacarpal bone and interosseous fascia, septum from the third metacarpal to the flexor digitorum profundus sheath, and hypothenar eminence
(C) Flexor tendons, superficial palmar aponeurosis, and thenar and hypothenar eminences
(D) Flexor tendons, thenar eminence, septum from the second metacarpal bone to the flexor digitorum profundus tendon, and superficial aponeurosis
(E) Septum from the first metacarpal bone to the superficial aponeurosis, septum from the third metacarpal to the flexor tendon sheath, and lateral and medial edges of the abductor pollicis muscle
The correct response is Option B.
The midpalmar space is one potential site of infection of the palm; others include the subcutaneous tissue, tendon sheaths, and thenar and hypothenar eminences. The midpalmar space is located deep to the flexor tendon. It extends dorsally to the fascia over the second and third volar interossei and the third and fourth metacarpals.
The midpalmar space is bordered radially by a fascial septum extending from the third metacarpal to the flexor sheath of the flexor digitorum profundus tendon of the long finger, and ulnarly by the fascia of the hypothenar musculature. The proximal margin of the midpalmar space is a thin layer of fascia that lies just distal to the carpal canal. The distal margin of the midpalmar space is bordered by vertical septa of the palmar fascia, which extend almost to the web spaces.
In patients with infection of the midpalmar space, diagnosis is often delayed. Affected patients typically exhibit swelling of the dorsal aspect of the hand, loss of palmar concavity, and difficulty extending and flexing the fingers. Marked tenderness in the midpalmar area is characteristic, and cellulitis is often associated.
The thenar space is located radial to the vertical septum between the third metacarpal and the flexor digitorum profundus tendon of the long finger; it extends to the radial edge of the abductor pollicis brevis tendon. The hypothenar space contains the hypothenar muscles and is enveloped within the fascia of these muscles. It is bordered radially by a fascial septum extending from the fifth metacarpal bone to the palmar fascia.
A 53-year-old man returns to the emergency department because he has redness, swelling, and severe pain in the left upper extremity two days after he sustained a laceration to the left hand. Current temperature is 102 °F (38.9 °C) and heart rate is 126/min. Current examination shows crepitus extending into the left forearm. Radiograph shows some gas in the soft tissue. Which of the following is the most likely causative organism?
A ) Eikenella corrodens
B ) Pasteurella multocida
C ) Pseudomonas aeruginosa
D ) Staphylococcus epidermidis
E ) Streptococcus pyogenes
The correct response is Option E.
The most likely causative organism is Streptococcus pyogenes (Group A Strep).
Necrotizing soft-tissue infections (necrotizing fasciitis) are rapidly progressive and potentially lethal. Symptoms usually begin with localized erythema and swelling and may mimic cellulitis in the early stages. Severe pain, crepitus, and systemic toxicity can provide clues to the diagnosis. Radiographs may show air in the soft tissues, and patients may exhibit grayish, watery discharge (dishwater pus). These infections can be caused by polymicrobial synergistic infections or may be monobacterial in nature. A recent study showed that group A streptococcus was the most common cause of monobacterial necrotizing fasciitis and that diabetes was the most commonly associated comorbidity. Early intervention and radical debridement are key to management of necrotizing fasciitis.
Eikenella corrodens is an anaerobic organism present in human oral flora and has been associated with human bite wounds.
Pasteurella multocida is a gram-negative anaerobic bacterium most commonly associated with cat bite infections.
Pseudomonas aeruginosa is a gram-negative rod that can be associated with diabetic wound infections.
Staphylococcus epidermidis is a gram-positive coccus present on the skin. It has been associated with implant infections.
Clostridial and beta streptococcal infections are the most common causes of early-onset necrotizing infection. Diabetes mellitus is the most common morbidity.
A 2 year old boy is brought to the emergency department because he has had lethargy, fever, and a rash over the extremities for the past 10 hours. Temperature is 39.9EC (103.8EF). Physical examination shows petechiae over the trunk and arms. Over the next three hours, the rash coalesces to hemorrhagic bullae, and the diagnosis of purpura fulminans is confirmed. Each of the following management interventions is appropriate EXCEPT
(A) administration of activated protein C
(B) broad-spectrum antibiotic therapy
(C) early wound debridement and amputation of ischemic digits
(D) fasciotomy of extremities
(E) fluid resuscitation with inotropic support
The correct response is Option C.
Purpura fulminans is a frequently fatal, rapidly evolving syndrome of septic shock and hemorrhagic bullae, which can result in massive desquamation. Management includes prompt recognition of the infection (which is usually caused by Neisseria meningitidis), initiation of broad €‘spectrum antibiotic therapy, mechanical ventilation, and aggressive fluid resuscitation with inotropic support. Disseminated intravascular coagulopathy (DIC) develops, and patients seem to benefit from replacement of activated protein C. A recently published multicenter, retrospective review of 70 patients documented an amputation rate of 90% and suggested the need for early fasciotomy to improve limb salvage. It is difficult to determine tissue viability during the resuscitation period; therefore, debridement, coverage, and amputation are delayed until demarcation has occurred.
A 29-year-old woman is evaluated because of a 2.5-year history of painful, draining lesions from the axillae and groin. Physical examination shows multiple nodules and abscesses. Conservative treatment with loose clothing, topical antibiotics, and antibacterial washes is unsuccessful. These findings are most consistent with which of the following disease processes?
A) Candidal infection of the intertriginous areas
B) Follicular occlusion of the apocrine sweat gland areas
C) Follicular occlusion of the eccrine sweat glands areas
D) Inflammatory and ulcerative skin condition mediated by neutrophils
E) Sexually transmitted infection caused by Klebsiella granulomatis
The correct response is Option B.
Hidradenitis suppurativa (HS), also known as acne inversa, is a chronic inflammatory disease of the skin and subcutaneous structures. Initially presenting as tender, subcutaneous nodules, the disease can advance to cause abscesses and large areas of subcutaneous scarring and draining sinus tracts.
Historically, HS has been thought to originate from the apocrine sweat glands. However, research in recent years has demonstrated that the mechanism is one of follicular occlusion: hair follicles become occluded due to an overproliferation of ductal keratinocytes, rupture, and subsequently re-epithelialize. As this cycle continues, sinus tracts form that house bacteria and cause chronic, painful infections and inflammation that can involve the skin and subcutaneous structures including muscle, fascia, and lymph nodes.
HS lesions typically occur predominately in the apocrine-gland bearing areas of the axillary, inguinal, perianal, and perineal areas. Lesions typically correspond with the “milk-line” pattern of apocrine-related mammary tissue in mammals.
Eccrine, or merocrine, sweat glands are found throughout the body, but their highest concentrations are in the palms and soles. These areas are typically spared by HS.
Follicular pyodermas, including folliculitis, furuncles, and carbuncles, arise primarily from the infection of hair follicles. They do not cause the sinus tracts, comedones, and scarring caused by HS.
Granuloma inguinale is a sexually transmitted infection of the genitalia, perineum, and/or perineal area caused by Klebsiella granulomatis.
Pyoderma gangrenosum is a dermatologic condition mediated by neutrophils that causes skin ulceration and breakdown.
An otherwise healthy 27-year-old man sustains a scorpion sting on a camping trip. Which of the following is the most appropriate management?
(A) Application of cold compresses
(B) Application of a tourniquet
(C) Administration of diazepam
(D) Administration of scorpion antivenin
(E) Debridement of the affected area
The correct response is Option A.
Because scorpion stings are typically self-limiting in adults, management should be limited to observation and application of cold compresses. Six closely related species of scorpion found in the southwestern United States cause medically significant injuries resulting from a sting. These species are typically 1 to 7 cm long and yellow-brown in color, possibly with vertical bands. The venom is neurotoxic, resulting in activation of the autonomic nervous system and depolarization of the neuromuscular junctions. Affected patients have intense localized pain and hyperesthesia; there is severe pain with light tapping over the area of the wound. Other symptoms seen in patients who sustain scorpion stings include blurred or diminished vision, strabismus, dyspnea, wheezing, dysphagia, urinary or fecal incontinence, opisthotonos, fever, and involuntary muscle contractions.
Hospital admission is recommended for children who have scorpion stings because envenomation is much more dangerous than in adults. Appropriate pediatric management includes airway control, sedation, cardiac monitoring for potential arrhythmias, and administration of calcium gluconate for treatment of muscle spasms. Narcotic agents should not be administered as they may exacerbate the neurotoxic effects. Scorpion antivenin is available for use in Arizona.
The use of tourniquets is not recommended in patients with scorpion stings. Debridement is not necessary because scorpion venom has only localized adverse effects on soft tissue.
A 60-year-old woman with type 1 diabetes mellitus has a 1-cm puncture wound to the lower leg sustained 2 days ago. Physical examination shows erythema of the surrounding tissue, tenderness of the entire calf, and crepitus. Which of the following is the most appropriate initial management of the wound?
A ) Hyperbaric oxygen therap
y B ) Silver sulfadiazine dressing
C ) Surgical debridement
D ) Unna boot compression dressing
E ) Vacuum-assisted closure therapy
The correct response is Option C.
The patient described has a severe, necrotizing soft-tissue infection, as suggested by tenderness and swelling of the entire limb compartment. Urgent debridement is required. Necrotizing fasciitis must be suspected in any patient with a compromised immune system, even when he or she has a relatively small surface wound. The infection spreads along deep tissue planes €”in this scenario, the muscle fascia. Severe inflammation may result in elevated compartment pressures, requiring fasciotomy. Intraoperative bacterial cultures should guide specific antibiotic therapy. Patients with severe continued or extensive necrosis may benefit from hyperbaric oxygen (HBO) therapy. After all of the necrotic tissue is removed, vacuum-assisted compression (VAC) dressings may be applied to expedite granulation. Definitive closure may involve healing by second intention, skin grafts, or flaps as clinically indicated.
A patient develops an infection at the wound site five days after beginning leech therapy. Which of the following is the most appropriate antibiotic therapy?
(A) Cephalexin
(B) Clindamycin
(C) Metronidazole
(D) Penicillin
(E) Trimethoprim-sulfamethoxazole
The correct response is Option E.
This patient has developed infection with Aeromonas hydrophila after undergoing leech therapy for five days. Medicinal leeches such as the Hirudo medicinalis species (which is the most commonly used leech and is endemic to Southeast Asia and Europe) can be applied to flaps or replanted limbs in order to relieve venous congestion. However, a common complication of leech therapy is the development of infectious organisms such as Aeromonas hydrophila, a gram-negative rod that can be detected in as many as 20% of persons within the first 10 days of therapy. Infiltration of Aeromonas hydrophila organisms can result in a rapidly progressive infection with gas in the soft tissues that can resemble clostridial myonecrosis. If infection does develop, trimethoprim-sulfamethoxazole is recommended for first-line therapy. Fluoroquinolones such as ciprofloxacin are also effective. Antibiotics that are still effective but less frequently recommended include antipseudomonal aminoglycoside, imipenem, meropenem, tetracycline, and second-, third-, or fourth-generation cephalosporins.
A 34-year-old woman comes to the emergency department 5 days after sustaining a cat bite to the left index finger. A photograph is shown. Medical history includes diabetes mellitus type 1. Physical examination shows punctures to the dorsum and volar surfaces of the proximal phalanx, mild fusiform swelling of the digit with tenderness over the flexor tendon sheath, pain with passive extension, and partially flexed posture of the digit. The symptoms have worsened over the past 3 days. Temperature is 99°F (37.2°C). Which of the following is the most appropriate next step in management?
A) Incision and drainage of the puncture sites
B) Inpatient intravenous antibiotics
C) Irrigation of the flexor sheath
D) Outpatient oral antibiotics
E) Splinting immobilization and elevation
The correct response is Option C.
The most appropriate option for this patient is to proceed to the operating room for decompression/drainage of the flexor tendon sheath. This patient has all four of Kanavel’s signs, specifically pain on passive extension, fusiform swelling, flexor tendon sheath tenderness, and flexion of the affected digit. These point towards a diagnosis of flexor tenosynovitis, with the cause being the cat bite she sustained several days prior. Although cat bites only reflect 5% of all animal bites, they represent 76% of all infected bites, thought to be because of the morphology of their long teeth, which simulate a deep puncture wound.
Outcomes studies demonstrate that because of this patient’s diabetes, she is at risk for a poor outcome, specifically the need for amputation and/or decreased total active motion. Other risk factors that can lead to these outcomes include age greater than 43 years, presence of subcutaneous purulence, digital ischemia, and polymicrobial infection. Given that she is at risk and that she has all four Kanavel’s signs, any intervention that is more conservative than operative decompression and drainage may lead to suboptimal outcomes.
Administration of antibiotics (orally or intravenously) is not a substitute for drainage of the flexor sheath, especially in a case that presents more than 48 hours out from initiation of symptoms. Drainage in the emergency department is not as optimal as in the operating room given that the infection may limit efficacy of local anesthesia as well as the need for possible conversion to an open drainage procedure if closed catheter irrigation is insufficient.
A 26-year-old man comes to the office because he has worsening pain and erythema in the thumb and small finger of the dominant right hand two days after he punctured the thumb with a wood splinter. The most appropriate initial step is exploration of the thumb, small finger, and which of the following?
(A) Dorsum of the hand
(B) Midpalmar space
(C) Parona space
(D) Posterior adductor space
(E) Ring finger
The correct response is Option C.
The radial and ulnar bursas are connected through the Parona space, which lies between the pronator quadratus fascia and the flexor digitorum profundus tendon sheath. The flexor tendon sheath of the small finger often connects with the ulna bursa, which extends proximal to the transverse carpal ligament. This connection can give rise to a €œhorseshoe abscess. € This abscess results when an infection starting in the thumb or small finger progresses proximal through the wrist and then into the opposite flexor tendon sheath through the Parona space. The Parona space can be explored by performing an extended carpal tunnel release.
Another potential space in the hand is the thenar space, which is bordered ulnarly by the vertical septum between the flexor sheath and metacarpal of the long finger, dorsally by the fascia of the adductor pollicis, and radially by the thenar muscle fascia. It should be noted that this space does not include the thenar muscles.
The midpalmar space is bordered radially by the vertical septum between the flexor sheath and metacarpal of the long finger, dorsally by the fascia over the interossei of the third and fourth web spaces, ulnarly by the fascia over the hypothenar muscles, and volarly by the flexor tendons.
The posterior adductor space is defined as the space dorsal to the adductor pollicis and volar to the first dorsal interosseous.
The dorsum of the hand contains the posterior interosseous space, which is dorsal to the first dorsal interosseous.
The ring finger would be explored if the patient had displayed signs of tenosynovitis of this digit.
A 45-year-old gardener with a 10-year history of poorly controlled type 2 diabetes mellitus comes to the emergency department because of excruciating pain and swelling of the left forearm 1 day after he scraped his left arm on a rosebush. Physical examination shows extreme tenderness, edema, and crepitus. Which of the following is the most appropriate management?
A) CT scan
B) Econazole
C) Hyperbaric oxygen
D) Immediate surgical debridement
The correct response is Option D.
Necrotizing fasciitis is a severe soft-tissue infection affecting the skin, subcutaneous tissue, and fascia. It characteristically spares the underlying muscle, progresses quickly, and is associated with high morbidity and mortality rates and severe systemic sepsis. The inciting event is often trauma, even minor trauma and small puncture wounds, but hematogenous spread is also a recognized etiology.
The vast majority of patients have some form of chronic debilitating disease that weakens the immune system. Diabetes mellitus appears to be the most common disease, but these may include substance abuse and renal failure. These patients are at higher risk for increased mortality.
Two types of necrotizing fasciitis have been described. Type I are mixed aerobic and anaerobic infections, with facultative anaerobic bacteria and non-group A streptococci being present. This is the most common type and is present in about 75% of cases. Type II infections are monomicrobic and are caused by group A Streptococcus species alone or in combination with staphylococcal species. For this reason, antibiotic coverage should be broad.
The disease progresses quickly but does evolve through several stages. Initial symptoms include tenderness, erythema, edema, warm skin, and fever; however, symptoms may vary depending on patient characteristics. Initial lab findings may include leukocytosis, thrombocytopenia, and hyperkalemia, but these are variable. When critical skin ischemia occurs, blisters or bullae are formed. In the late stage, lesions turn black and necrotic and are anesthetic as the nerves become involved.
Diagnosis begins with a high clinical suspicion in all patients, particularly those with risk factors. Appropriate treatment is surgical debridement, broad-spectrum intravenous antibiotic therapy covering gram-positive, gram-negative, and anaerobic organisms, and careful monitoring and correction of fluid and electrolytes in an intensive care setting.
Most authorities agree that hyperbaric oxygen is to be recommended for the treatment of necrotizing fasciitis as an adjunct, if facilities are available and there is no delay in surgical debridement. However, most studies regarding the efficacy of hyperbaric oxygen are anecdotal with a distinct lack of properly designed prospective randomized controlled trials.
Mortality rates are reported to be 10 to 75% and are increased in patients with underlying immune compromise, delayed treatment, or involvement of the chest wall.
A 47-year-old woman has a low-grade fever, chills, and pain and swelling of the proximal interphalangeal joint of the index finger. On examination, active and passive motion of the joint produces pain. There is no lymphangitis or lymphadenopathy. Which of the following is the most likely causative organism?
(A) Eikenella corrodens
(B) Neisseria gonorrhoeae
(C) Serratia marcescens
(D) Staphylococcus aureus
(E) Viridans streptococcus
The correct response is Option D.
In this patient who has septic arthritis affecting the proximal interphalangeal joint of the index finger, the most likely cause is infection with Staphylococcus aureus organisms. Staphylococcus aureus is an anaerobic gram-positive coccus that is present on the skin and is a frequent cause of skin and soft-tissue infections. It is the most common cause of septic arthritis of the hand and wrist.
Eikenella corrodens, an anaerobic gram-negative rod, is present in the human mouth and is more likely to be cultured from a human bite wound.
Septic arthritis resulting from Neisseria gonorrhoeae is more likely to occur in young men who are sexually active. Affected patients typically have a history of migratory polyarthralgia.
Serratia species are a frequent cause of infection in persons who abuse intravenous drugs as well as patients with diabetes mellitus or immune system compromise.
Streptococcus species, including viridans streptococcus, are the second most common causative organism in patients with septic arthritis of the hand.
A 70-year-old female with insulin-dependent diabetes sustained a superficial laceration of her left dorsal second web space five days prior to presentation for increasing pain and swelling. Examination revealed erythema, edema and tenderness over the dorsal and volar aspects of the second web space as well as the radial aspect of her palm. Which potential space can become infected with progression of the infection?
A) Thenar space
B) Parona’s space
C) Mid-palmar space
D) Dorsal subaponeurotic space
E) Natatory space
The correct answer is option a.
The thenar space extends from the third metacarpal to the thumb. It is contiguous with and separated from the midpalmar space by the midpalmar oblique septum. A collar-button abscess in the second web space will, like flexor tenosynovitis of the index finger, drain into the thenar space. Flexor tenosynovitis of the long and ring fingers and third web space infections will drain into the midpalmar space. Finally, small finger flexor tenosynovitis will track through the ulnar bursa and not the midpalmar space. The dorsal subaponeurotic space is just deep to the extensor tendons of the hand and does not communicate with the thenar or midpalmar spaces. Parona’s space is in the forearm between the superficial and deep flexor compartments. The natatory space is not a named space.
For each clinical scenario, select the most appropriate pharmacologic agent (A–E): A 19-year-old man has a seven-day history of swelling and pain on the volar surface of the left index finger. He has no history of trauma to the finger. Gram’s stain of fluid aspirated from the joint shows gram-negative diplococci.
A) Acyclovir
B) First-generation cephalosporin
C) Prednisone
D) Rifampin isoniazid
E) Third-generation cephalosporin
The correct answer is option E.
Septic arthritis may result from extension of an adjacent subcutaneous abscess or by intra-articular contamination caused by a laceration or puncture wound. The joint is a poorly vascularized potential space, favoring colonization. Early diagnosis and drainage are crucial to treatment, as a joint infection can progress rapidly to destruction of articular cartilage. The two most common organisms that cause hand infections are Staphylococcus aureus and B-hemolytic streptococci. Minor staphylococcal and streptococcal infections are treated with first-generation cephalosporins. More significant infections of the interphalangeal joint should be performed through a midaxial incision. Neisseria gonorrhoeae usually manifests as a primary venereal infection. However, it can disseminate and sometimes present as a secondary hand infection, which is often confused with a purulent tenosynovitis or arthritis. It is important to distinguish gonococcal from pyogenic infection because, unlike a pyogenic infection, a gonococcal infection does not usually destroy tendon or articular cartilage. Therefore, incision, drainage, and debridement are unnecessary and should be avoided. Disseminated gonococcal infection is the most common cause of acute infectious arthritis in sexually active adults. A history or evidence of trauma are lacking. Fluid aspiration with Gram staining for gram-negative diplococci allows definitive diagnosis. Hospitalization and intravenous administration of a third-generation cephalosporin is recommended. Manifestations of Sweet syndrome can masquerade as acute hand infections. Sweet syndrome, originally described as an acute febrile neutrophilic dermatosis, belongs to a class of skin lesions that histologically have intense epidermal and/or dermal inflammatory infiltrate of neutrophils without evidence of infection or vasculitis. The lesions can erupt at sites of minor trauma. The clinical picture is consistent with infection initially. The unresponsiveness of these lesions to antimicrobial therapy and the lack of associated cellulitis is a clue to the diagnosis. The treatment of choice involves a tapering dose of corticosteroids. Herpetic whitlows are often confused with paronychia or felon and are treated mistakenly as such. Initial signs include intense pain and erythema of the fingertip, followed by edema and tenderness. A Tzanck smear of vesicular fluid may show multinucleated giant cells. Primary herpes simplex infections typically resolve without treatment within three weeks. Incision and drainage of herpetic whitlow is contraindicated because surgical treatment converts a closed wound to open and may result in a secondary bacterial infection or viral superinfection. To date, there have been no controlled studies that assess the efficacy of acyclovir for the treatment of herpetic whitlow, but case reports suggest that it both suppresses and decreases the length and severity of recurrent infections when taken orally.
A 44-year old female presented to the emergency room complaining of increasing hand pain which began approximately two weeks prior. There was no history of chemical exposure, no history of trauma, and no known associated illness. She enjoyed excellent health and on examination the only clinically significant findings were confined to her hands, which are pictured in Figures 26a and 26b. She has not improved on intravenous cefazolin. The correct approach to treatment of this problem would be:
A) Debridement followed by immediate skin grafting
B) Metronidazole for anaerobic coverage
C) Empiric therapy with minocycline pending atypical AFB culture results
D) Local wound care and supportive therapy
E) Serial debridements
The correct answer is option D.
The lesion demonstrated represents pyoderma gangrenosum, which is a cutaneous lesion manifested by skin ulceration and necrosis. The onset is acute and rapid, affecting adults 25–54 years of age. In 30%–60% of cases there is an association with ulcerative colitis. It is much more common in the lower extremity and somewhat rare in the hands. Because of the unusual nature of the lesions, appropriate treatment is often delayed. Treatment is supportive including local wound care and sometimes the use of steroids, dapsone or cyclosporine. Surgical debridement may actually cause the lesions to proliferate. Skin grafting is occasionally needed, but never done during active disease. Treatment of the ulcerative colitis, when present, will also help to resolve the lesions. The etiology is not infectious, hence antibiotic therapies are not helpful.
A 49-year-old man with type 2 diabetes mellitus has had a “sausage” appearance of the left long finger from the metacarpophalangeal joint to the fingertip for the past two days. The finger is held in flexion at rest. On physical examination, there is tenderness along the volar aspect of the finger, and the patient has pain with passive extension.
Which of the following is the most likely diagnosis?
(A) Cellulitis
(B) Felon
(C) Osteomyelitis
(D) Paronychia
(E) Tenosynovitis
The correct response is Option E.
The most likely diagnosis is tenosynovitis, an infection involving the gliding surface of the flexor tendon sheath that typically develops following a puncture wound. Staphylococcus aureus is the most likely causative organism. The four essential signs of tenosynovitis are fusiform swelling, partial flexed posturing of the digit, tenderness along the flexor tendon sheath, and pain with passive extension of the digit.
Cellulitis is a common superficial infection that typically affects the dorsal aspect of the hand and is characterized by erythema, edema, and lymphangitis. Beta-hemolytic streptococcus is most frequently associated.
Felons are infections of the pulp space (which is compartmentalized by septa) typically caused by Staphylococcus aureus. Although tenosynovitis may develop in a patient with an advanced felon, the infection is more likely to be localized at the pulp initially, and the patient would have throbbing pain, especially when the finger is placed in a dependent position.
Patients with osteomyelitis have localized pain, swelling, and erythema along the course of one of the long bones of the hand. This condition often develops secondary to localized infection by hematogenous spread.
In patients with paronychia, the structures surrounding the proximal and lateral nail become infected. This condition is characterized by pain, especially in the region of the nail fold, and erythema. Staphylococcus aureus is the most frequently identified cause of acute paronychia, and Candida albicans is most likely to cause chronic paronychia.
A healthy 5-year-old boy is evaluated after he is bitten on the hand by a dog. He has an allergy to penicillin. Which of the following prophylactic antibiotic regimens is most appropriate to prescribe?
A) Amoxicillin and clindamycin
B) Ciprofloxacin and metronidazole
C) Clindamycin only
D) Doxycycline and metronidazole
E) Trimethoprim-sulfamethoxazole and clindamycin
The correct response is Option E.
The most appropriate prophylactic regimen to prescribe in this clinical scenario is trimethoprim-sulfamethoxazole and clindamycin.
Dog bites to the hand are potentially dangerous bites that could lead to serious hand infections. The common microorganisms that cause infections in such bites are Pasteurella species, anaerobes, Staphylococcus aureus, and Streptococcus. The ideal antibiotic would have been amoxicillin-clavulanic acid, which covers most of these microorganisms. However, the child is allergic to penicillin, and, therefore, this drug is contraindicated. Another good option would have been amoxicillin and clindamycin (for the anaerobic coverage). However, for the same reason described above, it too cannot be used. Tetracyclines are contraindicated in children under 8 years of age owing to the ill effects on growing teeth and bones. Quinolones are also contraindicated in children under 18 years of age owing to their harmful effects on cartilage and joints. Although this is debatable, currently the use of quinolones in children is restricted by the Food and Drug Administration to certain specific conditions (cystic fibrosis, multidrug-resistant urinary tract infection, and inhalational anthrax). Clindamycin alone does not adequately cover most of the organisms involved, including Pasteurella, which is gram-negative.
A 40-year-old man has a painful, fluctuant abscess over the dorsal aspect of the left hand at the level of the metacarpophalangeal joints. On physical examination, the index finger is abducted away from the long finger. This abscess most likely courses through which of the following anatomic sites?
(A) Extensor tendon sheath
(B) Flexor tendon sheath
(C) Palmar bursa
(D) Palmar fascia
(E) Parona’s space
The correct response is Option D.
This patient has a collar button abscess, which communicates from the volar web space to the dorsal aspect of the hand via the palmar fascia or lumbrical canal. Finger abduction is a characteristic finding. Appropriate management is drainage of the abscess using a combined volar and dorsal approach.
The extensor tendons do not lie within sheaths on the dorsal aspect of the hand.
Infection of the flexor tendon sheath is known as flexor tenosynovitis. This condition is diagnosed by the presence of one or more of Kanavel’s signs, including fusiform swelling, partial flexed posturing of the finger, tenderness over the flexor tendon sheath, and pain with passive extension of the finger. Finger abduction is not associated.
Patients with infection of the palmar bursa have a painful prominence in the palm without finger abduction.
Parona’s space lies between the pronator quadratus and flexor digitorum profundus tendons. It communicates with the flexor tendon sheaths to the thumb and small finger (radial and ulnar palmar bursa) and the midpalmar space. Infection within this space is characterized by painful swelling over the volar aspect of the wrist that occurs proximal to the flexion crease of the distal wrist.
A 15-year-old girl comes to the office because of a 1-day history of infection of the right index finger. Physical examination shows the tip of the finger is tender and swollen over the pulp. There is no history of trauma. Which of the following organisms is the most likely cause of this patient’s condition?
A) Candida albicans
B) Eikenella corrodens
C) Listeria monocytogenes
D) Pasteurella multocida
E) Staphyloccus aureus
The correct response is Option E.
Staphylococcus is still the most common organism in hand infections. The most common in felons is Staphylococcus aureus. Methicillin-resistant Staphylococcus aureus community-acquired (MRSA-CA) infections are now the most predominant strain in hand infections, comprising 60% of Staphylococcus aureus infections.
Pasteurella multocida should be considered with most animal bites, although it is most common with cat bites. Eikenella corrodensis associated with human bites. There is no history of bites in this case.
Listeria monocytogenes has been reported in flexor tenosynovitis in immunocompromised patients.
Candida albicans is usually associated with chronic paronychia.
A 55-year-old man comes to the emergency department because of acute onset of pain, swelling, and erythema of the right groin, lower abdominal wall, and right scrotum. He has type 1 diabetes mellitus which is controlled with insulin. He has smoked one pack of cigarettes daily for the past 30 years. He weighs 145 kg (320 lb); BMI is 35 kg/m2. Temperature is 38.3 °C (101 °F), pulse is 136 bpm, and blood pressure is 90/40 mmHg. In addition to admission to the hospital and administration of pain medication, which of the following is the most appropriate sequence in management?
A ) Intravenous antibiotics, hyperbaric oxygen, intravenous hydration
B ) Intravenous hydration, immediate surgical debridement, right orchiectomy
C ) Intravenous hydration, intravenous broad-spectrum antibiotics, CT of abdomen
D ) Intravenous hydration, intravenous broad-spectrum antibiotics, immediate surgical debridement
E ) Observation, intravenous antibiotics
The correct response is Option D.
The most likely diagnosis is Fournier disease. Diabetes mellitus, alcoholism, heavy smoking, leukemia, and AIDS can predispose to this condition. Common sources of infection include urogenital disease, trauma, or recent manipulation (iatrogenic trauma, ie, endoscopic procedures).
Key steps in treatment include early diagnosis, intravenous hydration, and broad-spectrum antibiotics (anaerobic coverage for Clostridium perfringens should continue as it is difficult to culture this). Immediate surgical debridement along fascial plains is of utmost importance. Orchiectomy is rarely needed, as testicles have their own blood supply and are protected by external spermatic fascia. Mortality rate is quoted to be 7% to 75%, with the higher rate in patients with diabetes, alcoholism, and in cases of delayed diagnosis.
A 21-year-old man with type 1 diabetes mellitus comes to the emergency department because of a large necrotizing, non-purulent infection after minimal trauma to the right cheek. Radical surgical debridement of the ulcer is performed, and the tissue is sent for histologic and microbiologic evaluation. Which of the following organisms are most likely to be found on light microscopy?
A) Chain-like collections of gram-positive bacteria
B) Grape-like clusters of gram-positive bacteria
C) Right angle nonseptate branching hyphae
D) Septate nonbranching hyphae and yeast forms
E) Tiny yeast forms with occasional unequal bud formation
The correct response is Option C.
Given the patient’s history of diabetes and necrotizing non-purulent infection after minimal trauma, he is likely to have mucormycosis, a life-threatening fungal infection caused by organisms from the class Zygomycetes. On microscopy, tissue samples from patients with mucormycosis demonstrate right-angle nonseptate branching hyphae.
Grape-like clusters of gram-positive bacteria is not appropriate. This option describes the characteristic appearance of a staphylococcal infection. Given the patient’s lack of cellulitis or purulent infection, it is an unlikely mechanism for this necrotizing ulceration.
Septate nonbranching hyphae and yeast forms is not appropriate. This option describes the characteristic appearance of a candidal infection. Given the patient’s lack of marked erythema and excoriation, and location of the infection on the face, rather than in skin folds, the likelihood of Candida as the primary pathogen is extremely low.
Chain-like collections of gram-positive bacteria is not appropriate. This option describes the characteristic appearance of a streptococcal infection. Although streptococcal infections are common in the head and neck region, the patient’s history and appearance of the lesion do not support Streptococcus as the causative organism.
Tiny yeast forms with occasional unequal bud formation is not appropriate. This option describes the characteristic appearance of Histoplasma capsulatum, an opportunistic fungus, which may cause marked pulmonary infections in immunocompromised patients.
Often emergent debridement is required, and that decision will need to be made on Gram stain, not on final culture.
An otherwise healthy 48-year-old nurse is brought to the emergency department because she has intense pain in the right lower extremity after sustaining a minor abrasion of the right knee. She has undergone evaluation twice within the past 48 hours for pain disproportionate to the level of injury. Temperature is 38.8 C (102 F) and blood pressure is 70/50 mmHg. On examination, the extremity is warm, swollen, and erythematous. There is a bluish blister at the site of injury. Laboratory studies show an increased leukocyte count, decreased platelet count, increased serum creatinine level, and increased international normalized ratio (INR). Radiographs show no abnormalities.
Which of the following is the most likely diagnosis?
(A) Clostridium necrotizing fasciitis
(B) Cutaneous anthrax
(C) Pseudomonas ecthyma gangrenosum
(D) Staphylococcal cellulitis
(E) Streptococcal toxic shock syndrome
The correct response is Option E.
This 48-year-old nurse has findings consistent with streptococcal toxic shock syndrome caused by invasive infection with Streptococcus organisms. This condition is characterized by pain disproportionate to the level of injury. Affected patients typically have other minor symptoms, in addition to pain, and have been known to seek treatment frequently before the correct diagnosis is established. Streptococcal toxic shock syndrome is confirmed by the presence of coagulation difficulties and hepatic and renal abnormalities.
Clostridial necrotizing fasciitis has symptoms similar to streptococcal toxic shock syndrome but is differentiated by subcutaneous emphysema and air in the tissues on radiographs.
With anthrax contamination, primary routes of inoculation are cutaneous and inhalational. Cutaneous anthrax is characterized by a single lesion that initially resembles an insect bite but then becomes ulcerated. Skin trauma is not associated.
Pseudomonas ecthyma gangrenosum is an infection that demonstrates rapid progression and is frequently fatal. It occurs in patients with febrile neutropenia, and is often a complication of chemotherapy administered for lymphoreticular malignancies.
Although staphylococcal cellulitis is not associated with systemic manifestations, patients with staphylococcal toxic shock syndrome can have failure of multiple organ systems.
All of the following factors are associated with an increased rate of amputation in the surgical treatment of diabetic patients with a hand infection except:
A) Renal failure
B) Deep infection
C) Insulin dependence
D) Gram-negative infection
E) Polymicrobial infection
The correct answer is option C.
A recent retrospective review of 45 patients with diabetes and surgically treated hand infections noted that insulin dependence, present in 31 patients, was not statistically related to a higher likelihood of amputation. Forty-six percent of the cultures were polymicrobial, which was associated with higher amputation rate. Other factors associated with a higher amputation rate were renal failure, deep infection, and gram-negative infection.
A 46-year-old woman comes to the emergency department because of a 5-day history of profound physical deterioration, nausea, and vomiting. She underwent breast reconstruction 3 weeks ago. Medical history includes delayed right latissimus dorsi tissue expansion breast reconstruction 1 year after completing radiation therapy. She has no other comorbidities. Physical examination shows erythematous rash involving and extending beyond the surgical sites. There are no notable fluid collections and the surgical wounds are not draining. Temperature is 103.5°F (39.7°C) and blood pressure is 90/50 mmHg. Laboratory studies show:
Intraoperative cultures of the explored surgical sites are most likely to grow which of the following organisms?
A) Bacteroides
B) Clostridium
C) Enterobacter
D) Pseudomonas
E) Streptococcus
The correct response is Option E.
The Centers for Disease Control and Prevention support criteria indicate that toxic shock syndrome may be diagnosed when patients present with a temperature exceeding 102°F (38.9°C), multisystems organ failure, rash, and/or multiple constitution symptoms.
Exotoxin1 and exfoliative toxin-producing Staphylococcus aureus are the most common pathogen, but enterotoxin A, B, and C, producing Streptococcus pyogenes infections, yield a worse prognosis. Blood cultures may be negative for the causitive organism.
Although Clostridium, Enterobactor, Pseudomonas, and Bacteroides species are polymicrobial species associated with necrotozing fasciitis, the description of this otherwise healthy patient is not consistent with its typical presentation of discolored blistered skin and crepitus.
A 34-year-old woman undergoes laser-assisted liposuction of the abdomen, hips, and inner and outer thighs using a tumescent technique. A total of 2500 mL of aspirate is removed. Postoperative recovery is uneventful, and the patient is discharged home the same day. She comes to the emergency department 4 days later with intense pain over the lower abdomen and flanks. Temperature is 101°F (38.3°C). Physical examination shows the skin has well-demarcated erythema, induration, and bullae forming at multiple sites. Her incisions are seeping clear, grey fluid. Which of the following is the most appropriate management?
A) Exploratory laparotomy for presumed bowel perforation
B) Intravenous administration of antibiotics and local burn care
C) Intravenous administration of antibiotics only
D) Oral administration of antibiotics
E) Surgical debridement of the involved tissue
The correct response is Option E.
Necrotizing fasciitis is a rapidly progressive soft-tissue infection characterized by necrosis of the fascia and subcutaneous fat with subsequent necrosis of the overlying skin. Although complication rates associated with liposuction are not unduly increased, infection is a major concern, and cases of prolonged inflammation, septic shock, and infections have been documented. Likewise, cases of necrotizing fasciitis following liposuction have been reported on several occasions and, according to data reported in the literature, the overall incidence of necrotizing fasciitis is equal to 0.4 per 100,000 patients.
There are two common forms that are reported: infections caused by Streptococcus pyogenes and mixed infections caused by a variety of microbes, including Escherichia coli, Proteus, Serratia, and Staphylococcus aureus. A detailed case of necrotizing fasciitis sustained by Mycobacterium chelonae after a combined procedure of liposuction and lipofilling has also been described. The progressive necrosis of the tissues typically involves the superficial fascia and the subcutaneous layer, but is limited in extension to the skin; the extent of the gangrene at the fascial layer is usually more severe and greater than at the skin level.
Necrotizing fasciitis is virtually unnoticeable in the first 48 hours with nonspecific symptoms. In the days that follow, an extensive, hardened region forms, which is often dark in the center. Severe pain and necrosis follow at the level of the infection.
Drainage of “dishwater fluid” is often pathognomonic. Metabolic changes occur, ending with respiratory distress, oliguria, acidosis, increased troponin concentrations, and sepsis. Diagnosis and treatment consist of surgical exploration and debridement that reveal necrotic, edematous, subcutaneous fat. Bacteriologic analysis of exudate, cultures, and histologic evaluation complete the diagnosis.
Early diagnosis is imperative to avoid a fatal outcome. Treatment is based on immediate and aggressive surgical debridement with combined antibiotic therapy. Because necrotizing fasciitis is a progressive, rapid infection, the wound typically is left open for a planned “second-look” operation and additional debridement if necessary. The mortality rates are increased and range up to 70% but decrease to 4.2% after immediate surgical intervention. Delay in debridement increases mortality.
A 40-year-old woman is undergoing chemotherapy for metastatic lung cancer. During administration of her first dose of doxorubicin, she reports pain at the site of injection. The following day, physical examination shows the hand to be swollen and an ulcer measuring 2 × 3 cm is seen over the dorsum surrounded by an area of ischemia. Which of the following is the most appropriate immediate treatment?
A ) Administration of hyperbaric oxygen
B ) Application of cold packs
C ) Application of hot packs
D ) Application of topical dimethyl sulfoxide
E ) Immediate surgical excision and autografting
The correct response is Option D.
The specific treatment of an extravasation injury is dependent on the drug infused. Application of topical dimethyl sulfoxide has been advocated for the treatment of extravasation of anthracyclines and is supported by several studies.
The value of hyperbaric oxygen therapy has not been proven. In the case of doxorubicin extravasation injury, cold compresses may exacerbate the complication by venous constriction, which localizes the drug, whereas hot packs may cause vasodilatation with further extravasation. Inflammation and pain can be managed with anti-inflammatory analgesics.
Early excision is rarely performed without evidence of at least ulceration, and the main indication would then be for pain control. In the scenario described, an option would be early surgical debridement and delayed closure of the wound; however, some of the surrounding skin may heal. Thus, a conservative initial approach with later excision after 2 to 3 weeks is recommended since this will give a better cosmetic result.
A 15-year-old girl has two draining nodules of axillary hidradenitis suppurativa. Each lesion is approximately 10 mm in diameter. The remaining axillary skin shows no abnormalities. After a 6-week course of oral doxycycline and topical mupirocin, the lesions drain less but are still present. Which of the following is the most appropriate treatment for this patient?
A) Complete axillary excision and skin grafting
B) Excision and closure
C) Incision and drainage
D) Intravenous antibiotics
E) Kenalog injection
The correct response is Option B.
This young patient has limited, focal disease that has failed medical management. Local excision is useful for isolated, scattered individual, or linear lesions. More extensive disease that occupies a significant portion of the skin area may be better treated by complete axillary excision. In this younger patient with limited disease, direct excision of the affected areas is a less morbid approach. Negative pressure wound therapy and skin grafts may be optimal coverage treatments for extensive disease, and some local flaps have been described as well. This stubborn disease originates from the apocrine glands and can often be chronic and disabling. The axillae, groin, perineum, and submammary areas can all be affected. Initial treatments include local care, antibiotics, hygiene, and weight loss. Steroid injections may help in early, small lesions, but have limited effectiveness and are painful. After a 6-week course of antibiotics, this patient is not likely to benefit from more treatment. Only excision of the diseased apocrine glands is likely to be effective. Incision and drainage is a suitable treatment for a closed abscess associated with hidradenitis, but incising this patient’s lesions would not improve her situation.
A 60-year-old woman who works as a nurse in the intensive care unit (ICU) is scheduled for cardiac bypass surgery. Because she has taken care of many patients with methicillin-resistant Staphylococcus aureus infection, she is interested in topical agents for decolonization. Which of the following regimens is most appropriate for this patient?
A) Clindamycin
B) Linezolid
C) Mupirocin and chlorhexidine
D) Trimethoprim-sulfamethoxazole
E) Vancomycin
The correct response is Option C.
The currently accepted decolonization protocol from the Infectious Diseases Society of America is a combination of topical nasal mupirocin ointment and a chlorhexidine body wash for 5 days. The most robust data for decolonization are in the cardiac surgery literature; the Society of Thoracic Surgeons guidelines recommend routine prophylaxis for all patients undergoing cardiac surgery. These guidelines are based on studies that show a decreased rate of sternal wound infections.
The carriage rate of methicillin-resistant Staphylococcus aureus for health care workers is approximately 5% based on large review studies. As a substantial portion of cases originate from nasal colonization, routine screening and decolonization are recommended in areas where the carriage rate exceeds 10% (Centers for Disease Control and Prevention recommendation).
The other antibiotics listed are reserved for the treatment of infection rather than as part of a decontamination protocol.
A 45-year-old man is brought to the emergency department with a Gustilo IIIB tibial fracture that he sustained falling off a tractor in a pasture. Medical history shows no drug allergies. Administration of which of the following antibiotics is most appropriate in this patient?
A) Amoxicillin
B) Ceftriaxone
C) Ciprofloxacin
D) Clindamycin
E) Vancomycin
The correct response is Option B.
The most appropriate antibiotic prophylaxis for this patient with a Gustilo grade III fracture is a third generation cephalosporin. Although much debate exists regarding antibiotic prophylaxis in open tibial fractures, it is generally accepted that antibiotic prophylaxis reduces the rate of infection. When antibiotic prophylaxis is not used, infection occurs in approximately 24% of open fractures. Thus, selecting the appropriate antibiotic, as well as duration, is of utmost importance. Antibiotic prophylaxis should be administered as soon as possible after injury and should be limited to a 72-hour course. In general, broad-spectrum antibiotics and multiple antibiotics should be avoided because they have been shown to increase the risk of nosocomial infections, including pneumonia. Of the antibiotics listed, the most appropriate choice for a patient with no drug allergies is ceftriaxone. Clindamycin and vancomycin should be reserved for cases of true penicillin allergy. Ciprofloxacin alone has been shown to be inferior to prevent infection after open tibial fractures.
A 25-year-old man comes to the emergency department because of swelling and pain in the finger. He says that he first started noticing symptoms 4 days ago. Physical examination shows warmth of the fingertip and fluctuance of the nail fold. A photograph is shown. Which of the following bacteria is the most likely cause of this infection?
A ) Enterococcus faecalis
B ) Mycobacterium marinum
C ) Pasteurella multocida
D ) Pseudomonas aeruginosa
E ) Staphylococcus aureus
The correct response is Option E.
A paronychia is an infection occurring in the space between the nail plate and the paronychial or eponychial fold. Common causes include nail biting and aggressive manicuring. In an otherwise healthy individual, Staphylococcus aureus and Streptococcus species are the most common pathogens causing a paronychia.
The remaining bacteria listed would only be expected to cause a paronychia in special circumstances. Enterococcus is an enteric bacterium. Mycobacterium marinum can be present in aquatic environments including fish tanks and has also been reported in the Chesapeake Bay. Pasteurella multocida is a common flora of cat mouths. Pseudomonas occurs in areas with moist environments and can be problematic in a burn unit.
An otherwise healthy 23-year-old man is brought to the emergency department after a motor vehicle-pedestrian collision causing compartment syndrome, myonecrosis, and need for radical resection of devitalized tissue of the right thigh. He is hemodynamically stable. A photograph taken two days after his first debridement is shown. Which of the following is the most appropriate next step in management?
A) Bilaminate neodermal reconstruction
B) Free contralateral anterolateral thigh flap
C) Negative pressure wound therapy
D) Skin grafting
E) Surgical debridement
The correct response is Option E.
Given the obvious devitalized tissue in the associated photograph, the most appropriate next step would be further debridement. This is an often overlooked, but still critical, cornerstone to reconstruction, because without it, complication rates from infection are significantly increased.
Debridement involves the removal of nonviable or contaminated tissue that impedes normal tissue growth. It renews the wound and surrounding tissue to promote normal healing by removing infection, biofilm, and senescent cells.
Different debridement options are available, including mechanical, biologic, technical, and surgical methods. In this acute scenario with an otherwise healthy patient and a large amount of devitalized tissue, surgical debridement is the most appropriate choice.
All other modalities/choices are not appropriate until the wound bed is stabilized. Negative pressure wound therapy may be used in conjunction with debridement, but is not a replacement for it.
An otherwise healthy 10-year-old girl is brought for evaluation because of a chronic ulcer of the right leg. The ulcer first appeared 6 months ago when she scraped her leg on a boat dock at her family’s lake house. The wound has increased in size despite treatment with a course of oral antibiotic therapy prescribed by her primary care physician. A photograph is shown. On evaluation today, the patient is afebrile and has no systemic signs of infection. Which of the following organisms is the most likely cause of these findings?
A) Candida tropicalis
B) Group A beta-hemolytic Streptococcus
C) Methicillin-resistant Staphylococcus aureus
D) Mycobacterium marinum
E) Vibrio vulnificus
The correct response is Option D.
The history and presentation are classic for an atypical mycobacterial infection. Unlike bacterial infections, atypical mycobacteria rarely produce systemic signs of infection and often manifest as a nonhealing (sometimes progressive) wound. Given the history of injury on a boat dock, the most likely causative organism is Mycobacterium marinum, an acid-fast bacillus that lives in water environments. This pathogen results in localized granulomas such as the one seen in this patient. Staphylococcus aureus is the most common source of skin infections but typically results in a more pronounced and acute immune reaction with localized redness and purulence. These findings are not present in this patient. Cutaneous infections with Group A beta-hemolytic Streptococcus and Vibrio vulnificus tend to increase rapidly and are often accompanied by severe systemic response (i.e., necrotizing fasciitis). Candida tropicalis is a fungus that is often part of normal skin flora. It is related to Candida albicans and can produce opportunistic internal infections in susceptible individuals.
A 27-year-old woman with a history of intravenous drug use has a persistent abscess and cellulitis of the dorsal aspect of the left hand. A photograph of the hand is shown. Three days ago, incision and drainage were performed using local anesthesia in the emergency department, and the patient was then admitted to the hospital for intravenous administration of piperacillin with tazobactam. Results of culture of the wound tissue are pending. Current physical examination shows that the cellulitis has not resolved satisfactorily. Which of the following is the most likely causative organism of this infection?
(A) Bacteroides fragilis
(B) Escherichia coli
(C) Group B streptococcus
(D) Pseudomonas aeruginosa
(E) Staphylococcus aureus
The correct response is Option E.
The infection described is most likely caused by a subset of Staphylococcus aureus, which is methicillin €‘resistant. Although methicillin €‘resistant S. aureus (MRSA) has traditionally been iatrogenic in its etiology, community €‘acquired MRSA is becoming more prevalent. In the Emergency Department population, the proportion of soft tissue infections presenting with MRSA is increasing. MRSA is not sensitive to penicillin €‘related antibiotics such as piperacillin/tazobactam and typically requires vancomycin or linezolid for effective treatment. Older antibiotics such as clindamycin and trimethoprim €‘sulfamethoxazole may also be effective in treating MRSA. MRSA takes longer than the other bacteria listed to grow out in culture.
Bacteroides fragilis, Escherichia coli, group B streptococcus, and Pseudomonas aeruginosa are all common bacteria found in abscesses of the hand; however, they are all sensitive to penicillin €‘related antibiotics such as piperacillin/tazobactam.
A 40-year-old woman with chronic hidradenitis suppurativa of the bilateral axillae is referred for surgical management after 4 years of local wound care, multiple corticosteroid injections, and oral antibiotics failed to improve her symptoms. Physical examination shows multiple inflamed nodules and draining sinuses. Photographs are shown. Which of the following treatment options is most likely to provide long-term resolution of this patient’s symptoms?
A) Axillary lymphadenectomy and coverage with a trapezius flap
B) Carbon dioxide laser and silver sulfadiazine
C) Fistulotomy and negative pressure wound therapy
D) Lesion excision and primary closure
E) Total axillary excision and skin grafting
The correct response is Option E.
Hidradenitis is a chronic and often disabling skin condition of the apocrine glands. It results in abscesses, inflammatory nodules, and draining sinuses in the axillae, groin, perineum, and occasionally the submammary area. It affects approximately 1 in 300 people, and it is more common in women, people who smoke, and people who are overweight. The axillae are more commonly involved in women, and the perineum more commonly in men.
Early treatment centers around local wound care, oral antibiotics, corticosteroid injections, hygiene, weight loss, and smoking cessation. Decreased estrogen levels may also contribute, and disease often subsides with oral contraceptives and during pregnancy. Unresponsive or extensive disease requires surgical intervention for long-term resolution. Relapse rates are high, and healing is often slow. Although limited excision and closure of solitary lesions is an effective short-term treatment, new lesions are likely to develop. Fistulotomy alone has an unacceptably high recurrence rate.
A long-term resolution in this severely affected patient requires complete excision of the hair-bearing skin of the affected area. The large defect created needs broad skin coverage. The best options include split-thickness skin grafting or grafting with negative pressure wound therapy immobilization. Negative pressure wound therapy followed by healing by secondary intention or coverage with local flaps are additional options, though scar contractures and shoulder stiffness are risks.
Laser treatments are too superficial to treat the deeper apocrine structures. Lymphadenectomy is not necessary for a cure.
A 40-year-old man presents to the emergency department because of the infection shown. Medical history includes type 2 diabetes mellitus, hypertension, kidney transplantation 5 years ago, and a 10 pack-year history of smoking (former smoker). Temperature is 39.7°C (103.5°F) and blood pressure is 80/45 mmHg, white blood cell count is 25,000/μL. He is transferred to the surgical intensive care unit for fluid resuscitation and intravenous antibiotics prior to operative debridement in six hours. Which of the following is the strongest risk factor for mortality in this patient?
A) Age
B) Delay in operative debridement
C) History of kidney transplantation
D) History of smoking
E) Type 2 diabetes mellitus
The correct response is Option B.
Necrotizing fasciitis is a rapidly progressive soft-tissue infection. Patients usually present with systemic sepsis, fever, high leukocytosis (higher than 25,000), skin findings of edema with blue discoloration, weeping blisters and cellulitis. The more severe cases can present with multisystem organ failure and altered mental status. Polymicrobial infections are most common. Streptococcal species are isolated in more than 60% of polymicrobial infections. Other organisms identified include Staphylococcus aureus, Escherichia coli, Pseudomonas, Enterobacter, Klebsiella, Proteus, Bacteroides, Clostridium, and Peptostreptococcus.
Multiple studies have reported a mortality rate of approximately 20% from necrotizing fasciitis. Mortality is directly proportional to time of intervention. Delayed surgical debridement has been shown to significantly increase the mortality risk. After diagnostic delay, the most common pitfall in treatment is inadequacy and delay in surgical debridement.
Type 2 diabetes mellitus is incorrect. Comorbid conditions such as diabetes, vascular disease and venous insufficiency are very common in these patients. Diabetes specifically is associated with higher morbidity and mortality. Studies have shown that patients with diabetes have a higher chance of a negative outcome compared to patients without diabetes. However, it has not been shown to be the most severe risk factor associated with mortality.
Smoking is incorrect. Smoking is a risk factor for delayed healing, but there are no studies that show smoking alone to be a risk factor in the progression of necrotizing fasciitis.
After delay of operative debridement, immunosuppression is the second most significant risk factor for mortality. Patients with solid organ transplantation or undergoing treatment for hematologic malignancies are most at risk. Age has been reported as another risk factor of mortality in patients with necrotizing fasciitis. Studies have shown that extremes of age, younger than 1 year or older than 60 years, were associated with mortality, but age is not the strongest risk factor among the others reported.
A 35 year-old I.V. drug abuser has a two-day history of fever, pain, swelling in his arm and redness as seen in Figure 35a. His blood pressure, on admission, was unstable. At the time of surgery, the soft tissue was edematous and dissected easily off the fascia. The fascia was necrotic but the underlying muscle was well vascularized, had good contractility and was of good viable color. Intraoperative photographs are seen in Figure 35b. At the time of surgery, a group A Strep was isolated both on cultures and gram stain. I.V. penicillin, in appropriate doses, was given with minimal response over the first 48 hours. What other treatment, other than debridement, should be instituted?
A) Hyperbaric oxygen therapy
B) Increasing the dosage of penicillin G
C) Adding clindamycin to the antibiotic regimen
D) Supporting appropriate measures for myoglobinuria
E) Placing wound vacs on for more appropriate wound care
The correct answer is option C.
The diagnosis is consistent with necrotizing fasciitis with an isolate of group A strep. The primary treatment includes adequate debridement, resuscitation and metabolic support. Pencillin is appropriate for treating the infection and clindamycin is beneficial to the resuscitative process. Large incolums of group A Strep cause significant muscle injury due to toxin production. Clindamycin prevents protein toxin synthesis at the ribosomal level. It also suppresses the growth of pencillin binding proteins.
A 48-year-old right-hand–dominant man with a history of cadaveric renal transplantation comes to the emergency department because of a swollen, painful left hand. A photograph is shown. He works as a crab fisherman and reports that he was bitten in the first web space by a crab 18 hours ago. He is taken to the operating room for emergent debridement. Intraoperative Gram stain shows a gram-negative, curve-shaped rod. In addition to aggressive surgical treatment, administration of which of the following antibiotics is most appropriate to treat this patient?
A) Cephalexin
B) Levofloxacin
C) Linezolid
D) Nafcillin
E) Vancomycin
The correct response is Option B.
Vibrio vulnificus is a common Vibrio species causing soft-tissue infections of the hand. Vibrio species are ubiquitous in aquatic environments including saltwater bodies. Immunocompromised hosts are at greater risk for amputation and death. The best chance for patient survival includes early diagnosis and initiation of appropriate antibiotics, as well as urgent surgical debridement for any evidence of necrotizing infection.
A broad range of antibiotics are effective against Vibrio species, including V. vulnificus. Agents effective against gram-negative rods, including quinolones, aminoglycosides, and aminopenicillins, are all effective against V. vulnificus. While all cephalosporins are effective against Vibrio species, third-generation cephalosporins are up to 130 times more potent than first- or second-generation cephalosporins. Vancomycin, nafcillin, and linezolid are all narrow-spectrum antibiotics, primarily effective against gram-positive cocci, and are not effective against Vibrio species.
A 21-year-old man comes to the emergency department 10 days after undergoing a septorhinoplasty, with new-onset fever, malaise, throat pain and a painful skin rash. He recently completed a course of amoxicillin and clavulanate potassium (Augmentin). Temperature is 39.1°C (102.4°F), blood pressure is 75/40 mmHg, and heart rate is 140 bpm. Physical examination shows multiple cutaneous blisters involving the face and entire trunk (45% total body surface area [TBSA]). Intraoral examination shows mucosal erythema and erosions. Nasal examination shows nasal septal splints that were placed at the time of surgery. The patient is admitted to the hospital. Biopsy of the skin rash shows full-thickness epidermal necrosis with dermal edema and sparse dermal infiltrates. Which of the following is the most likely diagnosis?
A) Acute generalized exanthematous pustulosis
B) Drug reaction with eosinophilia and systemic symptoms
C) Stevens-Johnson syndrome
D) Toxic epidermal necrolysis
E) Toxic shock syndrome
The correct response is Option D.
Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN) are in the spectrum of the same disease process, characterized by a severe drug-induced immune reaction. The drug or its metabolite acts as a hapten and provides antigenic stimulation for a T-cell–mediated delayed hypersensitivity reaction. The list of offending medications is extensive and includes antibiotics, anticonvulsants and NSAIDs. Onset is within the first 8 weeks of starting the medication, and is characterized by fever, mucositis and a painful generalized vesiculobullous rash. Histology of skin specimens reveals keratinocyte apoptosis, full-thickness necrosis of the epidermis, and minimal dermal inflammation. Mucosal inflammation can involve any mucosal surface. Cutaneous involvement consists of blisters and erosions, with skin separation. Application of shear forces on the skin results in separation of the epidermis (Nikolsky sign). Skin separation of less than 10% of total body surface area is classified as SJS, greater than 30% of total body surface area as TEN, and 10 to 30% of total body surface area as SJS-TEN overlap. Multisystem organ dysfunction can occur. Treatment is supportive, with the best outcomes in patients treated early in a burn center. Intravenous corticosteroids are usually given, although their use is controversial. Mortality is 1 to 5% in SJS and 25 to 40% in TEN. Survivors are often left with skin scarring, mucosal strictures, and ocular complications.
Toxic shock syndrome (TSS) is caused by toxin-producing strains of Staphylococcus aureus and Streptococcus pyogenes. The toxin acts as a super antigen and causes widespread immune stimulation. Staphylococcal Toxic Shock Syndrome can occur after surgical or traumatic skin break or from colonization of a foreign body. Onset is within 48 hours of surgery and consists of influenza-like symptoms, fevers, and shock. Multisystem organ failure can occur. Skin desquamation usually occurs 2 to 3 weeks later. Treatment consists of source control, antibiotic therapy, and in some cases, immunoglobulins.
Acute generalized exanthematous pustulosis (AGEP) is a T-cell–mediated cutaneous drug reaction. Onset is usually within 48 hours and consists of fever, leukocytosis, and a rash consisting of many small sterile non-follicular pustules distributed predominantly on the trunk and intertriginous areas. Mucous membrane involvement is uncommon and occurs mostly in the lips and buccal mucosa. Internal organ involvement occurs in a minority of cases but can lead to multisystem organ dysfunction. Histology shows intracorneal, sub-corneal, and intraepidermal pustules and a dermal neutrophilic and eosinophilic infiltrate. Treatment is discontinuation of the offending drug, after which the condition quickly resolves. Prognosis is excellent.
Drug reaction with eosinophilia and systemic symptoms (DRESS) is a severe drug reaction of unclear pathogenesis that is characterized by fever, hematological abnormalities (leukocytosis, eosinophilia), and internal organ dysfunction. Onset is typically 2 to 8 weeks after drug exposure. Antiepileptics are most commonly implicated, although a variety of drugs, including antibiotics, can be the causative agent. Cutaneous involvement consists of a morbilliform rash. Mucosal involvement is frequent. Facial edema can be severe. Blood leukocytes are markedly elevated, with 30% of cases having eosinophilia. Multisystem organ dysfunction can occur. Histopathology reveals a perivascular lymphocytic infiltrate in the papillary dermis and dermal edema with extravasated erythrocytes and eosinophils. Treatment consists of cessation of the offending drug, systemic glucocorticoids and supportive care.
A 25-year-old man is brought to the emergency department four hours after being bitten by a raccoon. He has not been previously vaccinated for rabies. In addition to irrigation of the wound, which of the following is the most appropriate management?
The correct response is Option D.
In a patient who has been bitten by a potentially rabid animal and who has not been previously vaccinated, management should include wound care and administration of both rabies immune globulin (RIG) and rabies vaccine. Because rabies incubation periods of more than one year have been reported in humans, the prophylactic regimen should be initiated immediately in any person who has been bitten by an animal with suspected or proven rabies regardless of the length of the delay, as long as clinical signs of rabies are not present. Studies have shown that a regimen of one dose of RIG and five doses of human diploid cell vaccine (HDCV) over a 28-day period is a safe treatment protocol that induces an excellent antibody response.
Immediate, thorough washing of all bite wounds and scratches with soap and water and irrigation with a virucidal agent (such as a povidone-iodine solution) are also important for preventing rabies. Experimental animal studies have shown that thorough wound cleansing alone without other postexposure prophylaxis markedly decreased the likelihood of rabies. In addition, tetanus prophylaxis and measures to control bacterial infection should be administered as indicated. Suturing of large wounds should be based on cosmetic factors and the potential for bacterial infection.
Prophylactic administration of both passive antibody and vaccine is indicated in all exposed patients except for those who have previously received complete vaccination regimens (preexposure or postexposure) with a cell culture vaccine or those persons who have been vaccinated with other types of vaccines and have had documented rabies antibody titers. Instead, these persons should receive the vaccine only. This combination of RIG and vaccine is also recommended for patients who have been exposed to rabies without specifically being bitten.
A 30-year-old man with AIDS is evaluated for a 6-week history of painless but increasing swelling of the flexor surfaces of the right wrist. Physical examination shows limited motion of the wrist and positive Phalen and Tinel signs. At the time of surgical exploration, rice bodies are present in the flexor tenosynovium. Which of the following is the most likely diagnosis in this patient?
A) Aspergillus fumigatus
B) Mycobacterium tuberculosis
C) Nocardia asteroides
D) Sporothrix schenckii
E) Vibrio vulnificus
The correct response is Option B.
Rice bodies are pathognomonic for tuberculosis.
Ziehl-Neelsen staining confirms the presence of acid-fast bacilli. All Mycobacterium and Nocardia species are potentially acid-fast. Many of these organisms are fastidious, so false-negative results are common. Surgeons should obtain multiple tissue samples and alert the laboratory that a diagnosis of tuberculosis is suspected. M. tuberculosis is traditionally cultured in Löwenstein-Jensen culture medium under specific temperature conditions 37.0°C (98.6°F). Histologic examination of specimens shows a granulomatous inflammatory process with the central portion of the granulomas appearing caseated.
If a mycobacterial infection is suspected, a Mantoux test should be performed. The test involves purified protein derivative injection into the dermis and evaluation of the cutaneous site after 48 to 72 hours.
M. tuberculosis should be considered in all immunocompromised patients. The other organisms can all be seen in hand infections in immunocompromised patients but do not produce rice bodies.
A 56-year-old woman develops a necrotizing infection of the abdominal wall (shown). Appropriate antibiotics are started and devitalized tissue is debrided. Which of the following interventions is most likely to decrease mortality?
A ) High-dose corticosteroids
B ) Hyperbaric oxygen treatment
C ) Intravenous gamma globulin
D ) Topical papain-urea ointment
E ) Vacuum-assisted closure device
The correct response is Option B.
Necrotizing soft-tissue infections are rapidly progressive, polymicrobial infections that require prompt diagnosis, debridement of devitalized tissue, and administration of appropriate antibiotics. Some studies have shown that mortality rates in necrotizing infections can be reduced with the addition of hyperbaric oxygen treatment. High-dose corticosteroids, intravenous gamma globulin, and topical papain-urea ointment have not been shown to increase survival rates of necrotizing soft-tissue infections.
To drain a thenar space infection, the dissection is carried out:
A) volar to the abductor pollicis brevis muscle
B) ulnar to the vertical septum between the third metacarpal and long finger profundus tendon
C) volar to the opponens pollicis muscle
D) volar to the adductor pollicis muscle
E) volar to the flexor pollicis longus tendon
The correct answer is option D.
The dorsal border of the thenar space is the adductor fascia, hence drainage of the thenar space entails dissection volar to that muscle. The thenar space is located radial to the vertical septum between the third metacarpal and the long finger profundus and extends to the lateral edge of the adductor pollicis. The space is bounded anteriorly by the thumb and index flexor tendons, posteriorly by the fascia over the adductor pollicis, radially by the thenar intermuscular septum and ulnarly by the midpalmar oblique septum. The abductor and opponens pollicis muscles are superficial (volar) to the thenar space.
